Expanded perlite (EP) is a microbial carrier used in microbial self-healing concrete (MSHC). However, the type of EP microbial self-healing agent (EPMSA) affects MSHC performance, especially with coupled carbonation and microbial-induced calcite precipitation (MICP). In this study, two EPMSAs were prepared (one coated and one uncoated by magnesium potassium phosphate cement (MKPC)) and two MSHC specimens were developed. The effects of carbonation on the carbonation depth, compressive strength, chloride penetration, and crack self-healing properties of MSHC were investigated. The results showed that the MSHC prepared with uncoated EPMSA had merely 1–2.2 mm carbonation depth and 63.8 MPa compressive strength after 28 days of carbonation. The uncoated EPMSA in MSHC induced more calcium carbonate than the coated EPMSA, thus improving the pore structure of MSHC, which is why MSHC exhibits high carbonation resistance and compressive strength. Although carbonation reduced the crack self-healing performance, the maximum healed crack width of MSHC incorporated with uncoated EPMSA could still reach 0.81 mm. Due to the positive effect of EP, MHSC has excellent resistance to chloride penetration. The dual action of EP and MICP makes uncoated EPMSA-incorporated MHSC exhibit excellent durability attributes. Using uncoated EPMSA is a more prudent approach when the strength and durability of MSHC are of critical concern.

中文翻译：

---

碳化作用对以膨胀珍珠岩为微生物载体的自修复混凝土性能的影响


膨胀珍珠岩 （EP） 是一种用于微生物自修复混凝土 （MSHC） 的微生物载体。然而，EP 微生物自修复剂 （EPMSA） 的类型会影响 MSHC 的性能，尤其是在碳化和微生物诱导方解石沉淀 （MICP） 耦合的情况下。在本研究中，制备了两种 EPMSA （一种涂覆磷酸镁钾水泥 （MKPC），一种未涂覆），并开发了两种 MSHC 样品。研究了碳化对 MSHC 碳化深度、抗压强度、氯化物渗透和裂纹自修复性能的影响。结果表明，未涂覆的 EPMSA 制备的 MSHC 在碳化 28 d 后仅具有 1–2.2 mm 的碳化深度和 63.8 MPa 的抗压强度。MSHC 中未包覆的 EPMSA 比包覆的 EPMSA 诱导了更多的碳酸钙，从而改善了 MSHC 的孔结构，这就是 MSHC 表现出高耐碳化性和抗压强度的原因。尽管碳化作用降低了裂纹自修复性能，但掺入未涂层 EPMSA 的 MSHC 的最大愈合裂纹宽度仍可达 0.81 mm。由于 EP 的积极作用，MHSC 具有出色的抗氯化物渗透性。EP 和 MICP 的双重作用使未涂覆的 EPMSA 掺入 MHSC 表现出优异的耐久性。当 MSHC 的强度和耐用性受到关键关注时，使用无涂层 EPMSA 是一种更谨慎的方法。